JP2010003475A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance component accuracy and component strength and inexpensively manufacture a fuel cell stack. <P>SOLUTION: A casing 24 includes end plates 20a, 20b arranged at both ends in the stacking direction of a stack 14; a plurality of side plates 60a-60d arranged on the side of the stack 14; and a hinge mechanism 64 connecting the end plates 20a, 20b and the side plates 60a-60d. The hinge mechanism 64 includes first hinge members 66a, 66b fixed to the end plates 20a, 20b; second hinge members 68a-68d fixed to the side plates 60a-60d; and connection pins 70a, 70b. The second hinge members 68a-68d are integrally bonded by stacking a plurality of flat plates 76 by caulking them. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a unit cell in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte is sandwiched between separators, and a stacked body in which a plurality of the unit cells are stacked is contained in a box-shaped casing. It relates to a battery stack.

  For example, a polymer electrolyte fuel cell employs an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane. A fuel cell is configured by sandwiching an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are disposed on both sides of the electrolyte membrane with a separator.

  Normally, this fuel cell is used as a fuel cell stack in which a predetermined number (for example, several tens to several hundreds) is stacked in order to obtain a desired power generation. In this fuel cell stack, the stacked fuel cells need to be reliably pressurized and held in order to prevent an increase in the internal resistance of the fuel cell and a decrease in the sealing performance of the reaction gas.

  Therefore, for example, a fuel cell stack disclosed in Patent Document 1 is known. In this fuel cell stack, a predetermined number of unit cells each including a joined body having an electrolyte interposed between an anode side electrode and a cathode side electrode and a pair of separators sandwiching the joined body are connected to each other. The laminates are electrically connected in series. End plates are disposed on the outside of the laminated body via current collecting electrodes, and the laminated body and the current collecting electrodes are accommodated in a case, and the end plate is a hinge mechanism. Is connected to the case.

JP 2002-298901 A

  In the above-described hinge mechanism, a plurality of hinge members (cylindrical insertion portions) are provided on the end plate, the case, and the like, and a connecting pin is integrally inserted into the hinge member. This type of hinge member is generally formed of a press product. For this reason, there is a problem that the roundness of the hole for inserting the connecting pin is difficult to obtain, and the component accuracy is low.

  The present invention solves this type of problem, and an object of the present invention is to provide a fuel cell stack that can be manufactured at low cost while improving component accuracy and component strength.

  The present invention includes a unit cell in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte is sandwiched between separators, and a stacked body in which a plurality of the unit cells are stacked is contained in a box-shaped casing. It relates to a battery stack.

  The casing includes an end plate disposed at both ends of the laminate in the stacking direction, a plurality of side plates disposed at the side of the laminate, and a hinge mechanism that connects the end plate and the side plate. . The hinge mechanism includes a first hinge member that is fixed to the end plate, a second hinge member that is fixed to the side plate, and a connecting pin that is integrally inserted into the first and second hinge members. The first hinge member or the second hinge member is configured by stacking a plurality of flat plates and integrally connecting them by caulking.

  Further, the first and second hinge members have holes into which the connecting pins are inserted, and at least the first hinge member or the second hinge member is located at two locations in the vicinity of the holes with respect to the flat plate. A caulking process is preferably performed.

  Furthermore, the first and second hinge members have a hole portion into which the connecting pin is inserted, and at least the first hinge member or the second hinge member is formed on a wall portion that forms the hole portion with respect to a flat plate. A caulking process is preferably performed.

  In the present invention, since a plurality of flat plates are laminated and integrally joined by caulking, the roundness of the hole into which the connecting pin is inserted can be maintained higher than the hinge member of the conventional press product. Therefore, the accuracy of parts can be easily improved.

  In addition, since the plurality of flat plates are integrated by caulking, stress is not concentrated on some of the flat plates when a load (shear load) is applied to the connecting pins. Thereby, it becomes possible to disperse | distribute stress uniformly to several flat plates, it prevents that a biasing force is added to a hinge mechanism, and component strength improves favorably. Furthermore, it is not necessary to weld or braze a plurality of flat plates, and the hinge mechanism can be manufactured inexpensively and with high accuracy.

  FIG. 1 is a partially exploded schematic perspective view of a fuel cell stack 10 according to the first embodiment of the present invention, and FIG. 2 is a partial sectional side view of the fuel cell stack 10.

  The fuel cell stack 10 includes a stacked body 14 in which a plurality of unit cells 12 are stacked in the horizontal direction (arrow A direction). A terminal plate 16a, an insulating plate 18 and an end plate 20a are sequentially disposed at one end in the stacking direction (arrow A direction) of the stacked body 14 toward the outside. At the other end in the stacking direction of the stacked body 14, a terminal plate 16b, an insulating spacer member 22 (the insulating plate 18 may be used) and an end plate 20b are sequentially disposed outward. The fuel cell stack 10 is integrally held by a casing 24 including end plates 20a and 20b each having a rectangular shape as end plates.

  As shown in FIGS. 2 and 3, each unit cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 30, and a thin plate-shaped first and second sandwiching the electrolyte membrane / electrode structure 30. Second metal separators 32 and 34 are provided. Instead of the first and second metal separators 32 and 34, for example, a carbon separator may be used.

  An oxidant gas supply for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the arrow A direction at one end edge of the unit cell 12 in the long side direction (the arrow B direction in FIG. 3). A communication hole 36a, a cooling medium supply communication hole 38a for supplying a cooling medium, and a fuel gas discharge communication hole 40b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge in the long side direction of the unit cell 12 communicates with each other in the direction of arrow A, and a fuel gas supply communication hole 40a for supplying fuel gas, and a cooling medium discharge communication hole for discharging the cooling medium. 38b and an oxidizing gas discharge communication hole 36b for discharging the oxidizing gas are provided.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 44 and a cathode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The anode side electrode 44 and the cathode side electrode 46 are uniformly coated with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 42.

  A fuel gas flow path 48 that connects the fuel gas supply communication hole 40 a and the fuel gas discharge communication hole 40 b is formed on the surface 32 a of the first metal separator 32 facing the electrolyte membrane / electrode structure 30. The fuel gas channel 48 is constituted by, for example, a plurality of grooves extending in the arrow B direction. On the surface 32b of the first metal separator 32, a cooling medium flow path 50 that connects the cooling medium supply communication hole 38a and the cooling medium discharge communication hole 38b is formed. The cooling medium flow path 50 is configured by a plurality of grooves extending in the arrow B direction.

  The surface 34a of the second metal separator 34 facing the electrolyte membrane / electrode structure 30 is provided with, for example, an oxidant gas flow path 52 composed of a plurality of grooves extending in the direction of arrow B, and this oxidant gas. The flow path 52 communicates with the oxidant gas supply communication hole 36a and the oxidant gas discharge communication hole 36b. A cooling medium flow path 50 is integrally formed on the surface 34 b of the second metal separator 34 so as to overlap the surface 32 b of the first metal separator 32.

  A first seal member 54 is integrally formed on the surfaces 32 a and 32 b of the first metal separator 32 around the outer peripheral edge of the first metal separator 32. A second seal member 56 is integrally formed on the surfaces 34 a and 34 b of the second metal separator 34 around the outer peripheral edge of the second metal separator 34. As shown in FIG. 2, a seal 57 is interposed between the first and second seal members 54 and 56 in order to prevent the outer periphery of the solid polymer electrolyte membrane 42 from directly contacting the casing 24. Is done.

  As shown in FIG. 1, rod-shaped terminal portions 58a and 58b projecting in the stacking direction are formed at substantially the center portions of the terminal plates 16a and 16b. For example, a load such as a vehicle travel motor is connected to the terminal portions 58a and 58b.

  The casing 24 is an angle member that connects end plates 20a and 20b, which are end plates, a plurality of side plates 60a to 60d disposed on the side of the laminated body 14, and end portions of the side plates 60a to 60d that are close to each other. (For example, L angle) 62a to 62d, and a hinge mechanism 64 for connecting the end plates 20a and 20b and the side plates 60a to 60d. The side plates 60a to 60d are made of, for example, a thin metal plate.

  The hinge mechanism 64 includes first hinge members 66a and 66b provided on the upper, lower, left and right sides of the end plates 20a and 20b, and second hinge members 68a to 68d provided at both ends in the longitudinal direction (arrow A direction) of the side plates 60a to 60d. And alternately arranged between the first hinge member 66a and the second hinge member 68a, between the first hinge member 66a and the second hinge member 68c, the first hinge member 66b, and the second hinge member 68a. A short connecting pin 70a that is integrally inserted between the first hinge member 66b and the second hinge member 68c, and between the first hinge member 66a and the second hinge member 68b that are alternately arranged, Between the first hinge member 66a and the second hinge member 68d, between the first hinge member 66b, the second hinge member 68b, and the first hinge member. 6b, provided with elongate connecting pin 70b that is inserted into integrally between the second hinge member 68d.

  The first hinge members 66a and 66b are formed with pin insertion first holes 72a and 72b, while the second hinge members 68a to 68d are formed with pin insertion second holes 74a to 74d. Is done.

  The first hinge members 66a and 66b are integrally formed with the end plates 20a and 20b, and the second hinge members 68a to 68d are configured separately from the side plates 60a to 60d. The second hinge members 68a to 68d are configured similarly, and, for example, only the second hinge member 68b will be described in detail below.

  As shown in FIG. 5, the second hinge member 68b is formed by laminating a plurality of metal flat plates 76 and integrally coupled by caulking. For example, each flat plate 76 is stamped with a metal blank material such as stainless steel having a thickness of 0.2 mm to 10.0 mm.

  A second hole 74 b is formed on one end of the flat plate 76, and a rectangular groove 78 is formed on the other end of the flat plate 76. The flat plates 76 are connected to each other through a dowel-caulking portion 80, and the dowel-caulking portion 80 is set at two locations in the vicinity of the second hole portion 74b. Each second hinge member 68b is joined by various joining methods by inserting the attachment plate member 82 into the groove 78.

  Note that the second hinge member 68b may be directly joined to the side plate 60b without using the attachment plate member 82. The first hinge members 66a and 66b are formed integrally with the end plates 20a and 20b. However, the first hinge members 66a and 66b may be configured in the same manner as the second hinge member 68b. .

  As shown in FIG. 1, the side plates 60 a to 60 d are formed with a plurality of screw holes 84 at both edges in the short direction, and the sides of the angle members 62 a to 62 d correspond to the screw holes 84. Thus, the hole 86 is formed. When the screws 88 inserted into the holes 86 are screwed into the screw holes 84, the side plates 60a to 60d are fixed to each other via the angle members 62a to 62d. Thereby, the casing 24 is configured (see FIG. 4).

  In addition, while forming screw holes in the angle members 62a to 62d and forming holes in the side plates 60a to 60d and arranging the angle members 62a to 62d inward of the side plates 60a to 60d, these are integrated. Alternatively, it may be screwed.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, an operation for manufacturing the second hinge members 68a to 68d will be described. For convenience of explanation, only the manufacturing method of the second hinge member 68b will be described below.

  Each flat plate 76 is punched by pressing, and two dowels 80a are formed in the flat plate 76 in the vicinity of the second hole 74b (see FIG. 6). One flat plate 76 is arranged so that the dowel 80 a faces downward with respect to the mold 90.

  Next, another flat plate 76 is laminated on the flat plate 76 such that the dowel 80 a is disposed in the recess of the flat plate 76 on the mold 90 opposite to the dowel 80 a. Then, the caulking process is performed so that the dowel 80 a of the upper flat plate 76 is pushed into the recessed portion of the lower flat plate 76. Thereby, the two flat plates 76 are integrally coupled to each other via the two dowel crimping portions 80.

  Similarly, the predetermined number of flat plates 76 are sequentially crimped on the mold 90. Therefore, the predetermined number of flat plates 76 are integrally coupled via the dowel crimping portion 80, whereby the second hinge member 68b is manufactured.

  The second hinge member 68b is joined to the mounting plate member 82 by inserting the mounting plate member 82 into the groove 78, and the mounting plate member 82 is fixed to the end of the side plate 60b.

  In the first embodiment configured as described above, the second hinge member 68b is formed by laminating a plurality of flat plates 76 and integrally coupled by a caulking process (the dowel caulking part 80). For this reason, compared with the hinge member of the conventional press product, the roundness of the 2nd hole 74b in which the connection pin 70b is inserted can be maintained high, and improvement of component precision is achieved easily.

  Moreover, the plurality of flat plates 76 are integrated by caulking. Therefore, when a shear load is applied to the connecting pin 70b, stress is not concentrated on some flat plates 76, for example, on the flat plates 76 at both ends in the stacking direction. This is because the flat plates 76 are integrally coupled to each other via the dowel crimping portion 80. As a result, the stress is evenly distributed to the plurality of flat plates 76, the biasing force is prevented from being applied to the hinge mechanism 64, and the effect of improving the component strength is obtained. In addition, it is not necessary to weld or braze a plurality of flat plates 76, and the hinge mechanism 64 can be manufactured inexpensively and with high accuracy.

  Further, the flat plates 76 are connected to each other by two dowel crimping portions 80. For this reason, the two dowel-caulking portions 80 have a detent function and can reliably prevent the flat plates 76 from rotating relative to each other.

  Next, the operation of the fuel cell stack 10 will be described. As shown in FIG. 4, an oxidant gas supply communication hole 36a of the end plate 20a is supplied with an oxidant gas such as an oxygen-containing gas, and a fuel gas supply communication hole. A fuel gas such as a hydrogen-containing gas is supplied to 40a. Further, a coolant such as pure water or ethylene glycol is supplied to the coolant supply passage 38a. For this reason, in the stacked body 14, the oxidant gas, the fuel gas, and the cooling medium are supplied in the arrow A direction to the plurality of unit cells 12 stacked in the arrow A direction.

  As shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 52 of the second metal separator 34 through the oxidant gas supply communication hole 36 a, and along the cathode side electrode 46 of the electrolyte membrane / electrode structure 30. Move. On the other hand, the fuel gas is introduced into the fuel gas passage 48 of the first metal separator 32 through the fuel gas supply communication hole 40 a and moves along the anode side electrode 44 of the electrolyte membrane / electrode structure 30.

  Therefore, in each electrolyte membrane / electrode structure 30, the oxidant gas supplied to the cathode side electrode 46 and the fuel gas supplied to the anode side electrode 44 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 46 flows along the oxidant gas discharge communication hole 36b, and then is discharged to the outside from the end plate 20a. Similarly, the fuel gas consumed by being supplied to the anode side electrode 44 is discharged to the fuel gas discharge communication hole 40b, flows, and is discharged from the end plate 20a to the outside.

  The cooling medium flows in the direction of arrow B after being introduced into the cooling medium flow path 50 between the first and second metal separators 32 and 34 from the cooling medium supply communication hole 38a. The cooling medium cools the electrolyte membrane / electrode structure 30, and then moves through the cooling medium discharge communication hole 38b and is discharged from the end plate 20a.

  FIG. 7 is a schematic exploded perspective view of the hinge mechanism 100 constituting the fuel cell stack according to the second embodiment of the present invention. In addition, the same referential mark is attached | subjected to the component same as the hinge mechanism 64 which comprises the fuel cell stack 10 which concerns on 1st Embodiment, and the detailed description is abbreviate | omitted.

  The hinge mechanism 100 includes a second hinge member 68b in which a plurality of flat plates 102 are stacked and are integrally coupled by caulking. The flat plate 102 is provided with a dowel crimping portion 104 on a wall portion that forms the second hole 74b, and the flat plates 102 are joined together. Although not shown, the second hinge members 68a, 68c and 68d are configured similarly to the second hinge member 68b.

  In the hinge mechanism 100 configured as described above, first, as shown in FIG. 8, each flat plate 102 is punched by pressing, and a ring-shaped dowel 104a that goes around the second hole 74b is formed.

  Next, the flat plate 102 is arranged so that the dowel 104 a faces downward with respect to the mold 106. The next flat plate 102 is arranged on the flat plate 102 such that the dowel 104 a faces the second hole 74 b of the flat plate 102 on the mold 106. Further, the dowel 104a is subjected to a caulking process, whereby the two flat plates 102 are integrally coupled.

  Similarly, the predetermined number of flat plates 102 are integrally coupled by applying a caulking process to the dowel 104a. Thereby, the 2nd hinge member 68b is manufactured.

  In the second embodiment configured as described above, the plurality of flat plates 102 are integrated by caulking, and the caulking process is performed on the wall portion forming the second hole 74b. For this reason, the same effects as those of the first embodiment can be obtained, and the second holes 74b can be easily positioned by the dowels 104a. Therefore, there is an advantage that the roundness of the second hole 74b can be more reliably increased as the entire second hinge member 68b.

1 is a partially exploded schematic perspective view of a fuel cell stack according to a first embodiment of the present invention. It is a partial cross section side view of the said fuel cell stack. It is a disassembled perspective explanatory drawing of the unit cell which comprises the said fuel cell stack. It is a perspective view of the fuel cell stack. FIG. 3 is a schematic exploded perspective view of a hinge mechanism constituting the fuel cell stack. It is explanatory drawing of the crimping process of the said hinge mechanism. FIG. 5 is a schematic exploded perspective view of a hinge mechanism constituting a fuel cell stack according to a second embodiment of the present invention. It is explanatory drawing of the crimping process of the said hinge mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Unit cell 14 ... Laminated body 16a, 16b ... Terminal plate 18 ... Insulating plate 20a, 20b ... End plate 22 ... Spacer member 24 ... Casing 30 ... Electrolyte membrane and electrode structure 32, 34 ... Metal separator DESCRIPTION OF SYMBOLS 42 ... Solid polymer electrolyte membrane 44 ... Anode side electrode 46 ... Cathode side electrode 48 ... Fuel gas flow path 50 ... Cooling medium flow path 52 ... Oxidant gas flow path 54, 56 ... Sealing members 60a-60d ... Side plates 64, 100 ... Hinge mechanisms 66a, 66b, 68a to 68d ... Hinge members 70a, 70b ... Connecting pins 76, 102 ... Flat plate 78 ... Groove parts 80, 104 ... Dowel caulking parts 80a, 104a ... Dowel 82 ... Mounting plate member

Claims (3)

A fuel cell stack comprising a unit cell in which an electrolyte / electrode structure having a pair of electrodes provided on both sides of an electrolyte is sandwiched between separators, and a stacked body in which a plurality of the unit cells are stacked is housed in a box-shaped casing. And
The casing includes end plates disposed at both ends in the stacking direction of the stacked body,
A plurality of side plates disposed on the side of the laminate;
A hinge mechanism for connecting the end plate and the side plate;
With
The hinge mechanism includes a first hinge member fixed to the end plate;
A second hinge member fixed to the side plate;
A connecting pin that is integrally inserted into the first and second hinge members;
And providing
At least the first hinge member or the second hinge member is configured by stacking a plurality of flat plates and integrally connecting them by caulking. 2. The fuel cell stack according to claim 1, wherein the first and second hinge members have holes into which the connecting pins are inserted,
At least the first hinge member or the second hinge member is subjected to two caulking processes in the vicinity of the hole with respect to the flat plate. 2. The fuel cell stack according to claim 1, wherein the first and second hinge members have holes into which the connecting pins are inserted, and
At least the first hinge member or the second hinge member is subjected to a caulking process on a wall portion that forms the hole portion with respect to the flat plate.

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